This is a multi-center, double-blind, placebo-controlled, randomized, parallel design trial of a novel antiepileptic drug (AED), ganaxolone. Subjects are patients with intractable epilepsy who will be hospitalized and AEDs withdrawn as part of routine clinical evaluation to determine their suitability for surgical treatment of epilepsy. Duration to one of the following will be the primary outcome measure: 4 seizures of any type, 3 generalized seizures, first-ever generalized seizure, or status epilepticus.